1. Field of the Invention
The invention relates to an electronic device and, more particularly, to an electronic device with an antenna.
2. Description of the Related Art
In wireless communication, a mobile device usually needs a competent transceiver system to maintain the two-way communication quality between the mobile device and the base station. A dipole antenna and a monopole antenna are usually disposed at the external surface of the mobile device or integrated to the mobile device. Another type of antenna used commonly is a planar inverted F antenna (PIFA), and the FIFA is usually configured in the mobile device. However, if the dimension of the antenna is large, it is not easy to integrate it to the mobile device.
Conventionally, a multiband antenna can be operated at multiple communicating bands by switching different matching circuits. However, an additional switch or a biasing circuit is needed, which makes the manufacture more complicated and the cost is increased.
As the mobile device becomes lighter, thinner and smaller, the space for disposing an antenna becomes narrower. Moreover, many components inside or outside the mobile device are made of metal, such as the metal housing, and the radiating loss of the antenna is large due to the electric field concentration, which makes the manufacture of a multiband antenna more difficult.